form input {
    width: 100%;
    height: 100%;
    outline: none;
    border: none;
    background-color: transparent;
    padding-left: 5px;
}

form .input-box {
    position: relative;
    width: 100%;
    height: 35px;
    border-radius: 5px;
    background-color: var(--b-gray);
    overflow: hidden;
    box-shadow: 18 18px 30px var(--b-gray-rgb-5);
    display: flex;
}

form .input-box i.line {
    position: absolute;
    height: 2px;
    bottom: 0;
    left: 50%;
    right: 50%;
    background-color: var(--b-main);
    transition: all .2s ease-in-out;
}

form input[type="text"]:focus+i.line,
form input[type="password"]:focus+i.line,
form input[type="text"]:valid+i.line,
form input[type="password"]:valid+i.line {
    left: 0;
    right: 0;
}

form input[type="submit"],
form input[type="button"] {
    width: 250px;
    height: 35px;
    border-radius: 5px;
}